akshay67

What's more damaging to the engine, high speed, e.g. constant 120mph in 5th; or high revs, e.g. constant 80mph in 3rd (6800rpm)?

ktomass

Both!

Chaddy

Depends what your worried about damging,on the basis that 120 mph in 5th isn't as high rpm as 80 in 3rd, then engine damage would be worse at 80 in 3rd, to hold a constant 6800 rpm in any gear doesn't sound like a very good idea ! It also depends on what you mean by constant speed, do you mean just level throttle, to maintain the speed on say a level road, or up a steep hill or high load situation e.g.towing i.e. full throttle.

akshay67

Cheers Chaddy, just something I was wondering about when driving on the motorway. (So level road).

It's a well known fact that holding an impreza at a high speed for a long time is not the done thing. Now does this extend to high revs too? I guess it does!

scoobyslut

High RPM is a killer as you appreciate, butas you also see, continued high speed, can also prove limiting as regards engine life. I would suggest for continued motorway driving,adopting a regime of "X" miles at "X" mph and followed by "X -10" miles at "X-10" mph and swop between the two, it also helps to relieve tiredness too, as you have something else to think about.

Sorry, I know you guys dont have speedo's with an "X" mark on, so use a bit of "common", as thats why I dont put speed limits down either!
Keep em cruisin'......

Ste

Leslie

As ktomass says, both are bad for the engine. I understand that this engine does not like sustained high revs and often will lose a big end after a bit too much of that. It is usually safer to change up a bit earlier, maybe at 6300 since you will not gain very much in extra acceleration, but it will stress the engine quite considerably at the higher RPM.

Les

elgordano

but isn't this true of all cars !!!

Gordo

Gridlock Mikey

STOP,STOP,STOP,STOP

What's with the words BAD and KILLING the engine Holy **** guys Best I never go over 3,000 rpm and god help me if i do more than 70mph!

I think you'd be more accurate if you talked about wear and tear. Revs and Load affect the longevity of an engine and as already stated, it's the same for all engines, well machines in general come to think of it.

There's nothing wrong with booting an Impreza down a country lane like there is nothing wrong with doing 100mph on the motorway (Mechanically I mean not legally ) It's a straightforward 2 ltr Turbo engine,I could be improved in a few area's it's true, but predominantley its a very successful reliable engine, that can take a moderate amount of stick, day in day out, that's it, not a time bomb waiting to blow/fail.
Enjoy the bladdy thing and excercise common sense and a bit of mechanical sympathy and it will be fine. Razzing everywhere in 2nd gear isn't common sense by the way

Mikey

misty

Well said that man!!
dave

akshay67

But it is so much fun

And yesterday I realised that 3rd gear on the motorway is so much fun too...60-90 neck-snapping action

my94

lol

swaussie

I for one drive in Germany every chance I get and have probably done in excess of 2000-3000 miles of sustained high speed driving (over 120 mph) with several track days and touch wood haven't noticed one ouce of difference with the car. It doesnt use any more oil, shake, stutter, have any noises, etc. It does use stupendous amounts of petrol at those speeds but it still fires first kick in the morning and runs like a dream. I agree with the above that they are not all going to go pop every time you hit 140mph.

Mick

iTrader: (1)

Ideally do 80 in 5th - you then are more likely to keep your licence & engine intact - to do the fun stuff on the few places left with out speed cameras

Mick

Chaddy

akshay,
Something occurred to me on the way home last night, 6800rpm in 3rd is about 90 mph not 80 mph..what are you driving? 120 mph in 5th is around 5000 rpm maybe a bit less. Although more power, therefore more load on the engine, is required for high speed, I still think that high revs are the real potential killer, 6800 rpm is nearly on the limiter. I'm sure the Scooby would run all day at just less than 5000 rpm, but I'm not so sure it would run all day at 6800 rpm !

Leslie

Gridlock,

I don't think anyone said anything different to what you did, just differently thats all.

Les

akshay67

Chaddy, you are right. I tried to pull some figures off the top of my head to illustrate a high rev vs high speed situation.

Driving in 3rd on the motorway is like having an anti-lag kit Also rather stupid I suspect

[Edited by akshay67 - 12/4/2003 2:00:08 PM]

MadMax-STI

my veiws r as long as u regulary service it, (top quality oil is a must) you will not harm it at all, thats why a rev limiter is incorperated into the engine managment.
ive recently gettin an STI COUPE and i cane it quite often, 8500 rpm every gear and it loves it, me too quite often hitting limiter in top gear 8500-8600 rpm 158 mph i just love the buzz, cant get enough
this wont hurt the car at all and i have loads ov respect for it as its ma pride and joy.. so *** on u sunday drivers give give it sum hammer, thats wat youve bought it for isnt it !!!!

MadMax-STI

also well said "gridlocker mick"

SiHethers

MadMax

High speed/rev combo is the single most common factor prior to STI engines doing their big-ends. It's due to a number of factors, but detonation is the big one. The bonnet scoop (and hence intercooler) is next to useless above 110-120mph. Also, unless you car has been remapped for UK fuel, or you use optimax + octane booster only, your car may be detting all the time (jap models are mapped for 100-102 RON)

Would hate to see your pride and joy spit its pistons out after only a short spell of enjoyable ownership

Cheers

Simon

Edited to say this is more important for classic shape models than bugeyes.


[Edited by SiHethers - 12/4/2003 4:21:52 PM]

barneyrubble

Bloody hell paranoia setting in. It's a machine - respect it, look after it but enjoy it without being too paranoid and unless you are unlucky it should be fine as Subaru win awards for reliability dont they?

bit bloody thirsty though but you have to pay to play!

muly

Have to agree with the respecting your car and a good service ,but these cars were built to be driven hard,i'm about to get my 2nd classic wrx ,but before i got my first 1 i was nearlly put off from buying 1 as this site has loads of "watch for deting, use this oil,this petrol, watch big ends etc"i almost thought they must be built from paper,as my previous car was a 2wd cosworth and running 280bhp for 3yrs never let me down and that was 3yrs of stick,but good services, just hope i can get the same reliability from my next scoob

ktomass

"What's more damaging to the engine, high speed, e.g. constant 120mph in 5th; or high revs, e.g. constant 80mph in 3rd (6800rpm)?"

If you ask a question like this, what type of answers do you expect!? It would be rather stupid to run your car on a motorway in 3rd at 6800rpm, that is why technitians have developed 5 (or more)speed gearboxes.

I'm not saying you will destroy your car driving like this but in time it could get you there. That's all. Use commons sense (as far as i'm concerned constant 6800rpm in 3rd is not!) and the car will work fine; they were built to be driven hard but in "normal road language".

Kristijan

akshay67

I didn't mean an entire motorway jouney in 3rd! Just a couple of minutes for some fun...strolling in 60 and then shooting to 90 - fun aplenty (maybe not for the engine?!).

BTW, I asked the question genuinely - didn't expect a particular 'type' of answer

Pavlo

High testosterone (sp?) will do the most damage every time.

Paul

fizzled

the answer to this question in my experiance is neither but (A RAPID CHANGE IN ACCELERATION OR DECELERATION) or an attempt to do so. eg they can run engines on test beds for years at full power and have no problems. i dont know but food for thought.

DaveD

iTrader: (2)

I've now had my 100,000 mile, '93 WRX for 4 years....
In those 4 years I have regularly driven it hard (several hours of driving at a time bashing the red line in each gear) and have also driven at sustained speeds above 120mph for over half an hour at a time in France in temps over 25 degC. Cruising at 80mph = 4,000 revs, and I normally drive like this for about 500 miles a month.

Sure, all those revs have probably reduced the life of the engine, but so would driving everywhere under 2,000 rpm to some degree.

I bought the car to have fun, and that's exactly what it does.

I think you are far more likely to do damage by revving the car excessively when cold, and by doing short stop/start journeys. When the engine is up to temp, all the tollerences are as they were designed to be, and I think Subaru designed the engine to last for more than 6 months.......

So in summary, provided the oil and water is looked after, and given a bit of sympathy when cold, the engine should be able to cope with just about anything you chuck at it. Treat it like any other car.

muly

Great stuff Dave, using the car how it was meant to be used ,for all those who dont agrea ,stop using your scooby as a status symbal and by a Rover